Peripherals attach to computers and other electronic devices to add functionality. Wireless modems are an example of one type of peripheral. An external wireless modem can be connected to a computer or other device using a standard data bus, such as a Universal Serial Bus. A wireless modem allows a computer to wirelessly communicate with a communications system, such as a cellular system. During operation of the modem, the modem transmits and receives wireless signals to and from the communications system. In some instances, the communications system requests that the modem increase the transmit power of its signals. The modem can increase the transmit power up to a maximum transmit power.
Some peripherals, including some wireless modems, are powered by a power supply located in the device to which the modem is connected. However, it is frequently the case that these external power supplies are insufficient for the peripheral. For example, with a wireless modem, increasing the transmit power of the modem increases the current draw of the modem. As a result, the increased transmit power can cause the modem's current draw to exceed the maximum current available from the external power supply in the attached device.
To overcome this problem, some wireless modems include internal batteries to handle their extra power needs. However, in these modems, the internal battery must be separately charged, which typically requires an additional power adapter and cable. Other solutions, such as ganging host device ports connected to the peripheral to supply additional power, are not available in all circumstances.
Thus, there is a need for a wireless peripheral that offers a more elegant solution the power limitations often faced by peripheral devices.